The OP is not asking about setbacks. And if you look at the first photo it appears as if the proposed addition is not any closer to the street than the existing house. So kind of an irrelevant comment.

There's no easy answer to the roofline dillema. I agree that the two slightly different colored tiles would be strange. Possibiities include using a completely different material, arranged in such a way that the two materials don't touch, or putting a flat roof over the addition, which might not work where you live.

The setback in our area is 25 feet and we are no where near that. We have plenty of room for the addition if we can figure out how to do it.

I’m confused by ‘we don’t want to tie into our existing roof anywhere’. That to me means building a freestanding building

From the pictures and the plan, I can't figure out where your new garage will be. Does the new garage open to the back of the property? The fence line (if it is a property line) does not appear to give enough room, but, of course, I am sure you know what space you have. I am just trying to figure out how that addition connects to the house. Which wall of the existing garage is adjacent to the house? (The two windows in the existing garage make it appear that the new garage faces the back of the property).

It's not clear where the new garage will go. You might want to mark up the image or show more of the plan (a plot plan showing the house and addition on the lot).

Also, we are in a hurricane zone so we built to gold standard for insurance purposes. We do not want to tie into the existing roof anywhere because of that.

Could you explain? How can you not "tie into" the existing roof?

So our designer is having trouble with the roof lines.

Maybe that indicates it's time for a new plan, a new designer, or both.

I agree that I have no clue where this new garage is going since it appears to me as if it is going in front of the house which IMO will not be a good idea. BTW you need an architect to do this not a designer. The only way to not tie into the existing roof is to build a free standing building and honestly I see no space for that . I think a lot of work and money for a space the kids will out grow in no time.

Looks like the plan is flipped

I am sorry. I see the confusion now. We purchased the lot next door so the addition will go to the west of the house with a west side entrance. I have attached more pics to clarify, I am also attaching two pics of how I thought the roof might tie in to the side of the house vs the existing roof but did not not know if someone had a better idea. Thanks for the feedback and sorry for the confusion.

They were just added to the original pics up above.

My only suggestion is to raise the roof of the new garage enough so that the two roofs don't physically meet. But you will still have the issue of the existing roof draining towards the new structure, which is best solved by eliminating the hip and extending the gable to the new garage. Not sure, but perhaps enough tiles could be salvaged so no new tiles would be required.

This will extend the garage to kitchen route -- and add stairs -- two things I'd dislike. Is there another option for adding the desired playroom/family room/whatever?

We have tried to think of any other possibility and it seems like we are left with this option. We can’t go forward because of setbacks and can’t go back because there is a 15 foot drop so we built a chain wall and pool on the original design. Expanding to the west seems to be the only option. The playroom is for our 4 grands that are currently age two months to 5 years. We watch them daily and when we built the house 6 years ago we had zero grand children. All of their toys are currently piled in our office and we are desperate for added room. The garage conversion would be an additional room with a Murphy bed so it could have multiple uses. The discontinuing of our current roof color was another curve ball but the new shade would just be a little darker so a possibility.

What are the steps in the old garage for? Do you need a full bath? Would a powder room do? Do you need stairs from the back yard and a deep closet. Could some of the above be move into the old garage space, so its footprint doesn't change. Can you detach the garage and rotate it?

Instead of adding a garage, could you add on a new space directly behind the existing one?

I am not sure if you can get the idea from this pic but we can’t go behind the existing garage because a storage area was built there in original construction and we would hate to lose the money spent building it and we use it for all external storage. But thank you for the suggestion.

The new steps in the old garage will be to access the attic for storage and to maintain ac units etc. which are already up there, that is why the attic access has to stay where it is. We need a walk-in closet to organize all of the toys, art supplies etc., and a full bath but did not want to take up any more room in the old garage because of the stairs. We also needed access from the backyard without having to walk all the way around the house. I do agree a dettached garage would make the most sense and may have to revisit that option. I was just trying to avoid it because of the weather factor (getting groceries etc. in the house without wind driven rain, freezing, etc.) . I really want to thank everyone for their input!